Stock-Based Compensation Plans (Additional Information) (Details) - USD ($)			12 Months Ended
		May 01, 2012	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	[1]		58,743	219,399
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	[1]		157,956
Proceeds from Stock Options Exercised			$ 1,300,000	$ 736,000
Percentage of total compensation			4.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	[1]		49,293
Stock Option and Incentive Plan 2003 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares of stock reserved and available for issuance		1,200,000.0
Stock Option and Incentive Plan 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation, vesting period			5 years
Stock based compensation, option granted, contractual life			10 years
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation			$ 30,000	51,000	$ 81,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense			36,000	59,000	19,000
Unrecognized compensation cost for nonvested stock options			$ 48,000
Unrecognized compensation cost, recognition period			3 years 1 month 6 days
Total intrinsic value of options exercised			$ 2,500,000	573,000	134,000
Restricted Stock Awards and Management Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation			805,000	393,000	321,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense			$ 282,000	137,000	112,000
Unrecognized compensation cost, recognition period			2 years 7 months 6 days
Unrecognized compensation cost related to nonvested shares			$ 1,100,000
Management Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price as a percentage of fair market value on the date of grant			0.00%
Stock based compensation, vesting period			2 years
Share-based compensation			$ 102,000	66,000	67,000
Granted			16,000
Long-Term Performance Share Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	[2]		$ 1,080,000	330,000	151,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense			$ 378,000	116,000	53,000
Unrecognized compensation cost, recognition period			1 year 5 months
Unrecognized compensation cost related to nonvested shares			$ 417,000
Granted			17,385
long term performance plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	[2]		$ 84,000
Deferred Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation			$ 81,000	$ 62,000	$ 46,000
Unrecognized compensation cost, recognition period			10 years 4 months 18 days
Unrecognized compensation cost related to nonvested shares			$ 308,000
Percentage of total compensation			10.00%
Percentage vested on 65th birthday			100.00%
Granted			4,094	3,609	3,030
Qualified Stock Options [Member] | Stock Option and Incentive Plan 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price as a percentage of fair market value on the date of grant		100.00%
Nonqualified Stock Options [Member] | Stock Option and Incentive Plan 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price as a percentage of fair market value on the date of grant		85.00%
SBM Financial, Inc. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	[1]			118,299
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	[1]		109,356
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	[1]		8,943
SBM Financial, Inc. [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense				$ 378,000
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income			$ 72,000

[1] (1) Options outstanding at January 1, 2016 included 118,299 of non-qualified stock options issued in conjunction with the Merger. Of these, 109,356 were exercised during 2016. At December 31, 2016, 8,943 non-qualified stock options issued in conjunction with the Merger were outstanding and exercisable.

[2] (1)For the year ended December 31, 2016, $84,000 of compensation expense associated with the LTIP for the plan year January 1, 2016 to December 31, 2018 was accounted for within total compensation expense for restricted stock and restricted stock units above as this plan contains both performance- and service-based conditions.